a beam of invisible particles or waves emitted by a [...]

Oncologists (cancer treatment physician) specialized in the use of radiation [...]

time at the end of which half the atoms initially [...]

spontaneous disintegration of a nuclide during which energy is liberated, [...]

a radioactive substance not-intended for human use

a chemist specializing in the manufacture of radioactive substances, therefore [...]

chemistry of substances incorporating a radioactive element

an element where all the isotopes are radioactive, like for [...]

radioactive isotope, an unstable isotope that decays over the course [...]

specialist in x-ray imaging